THORLABS SPCM A Series User manual

Single Photon Counting Module
SPCMxxA
Quick Start
2020

Version:
Date:
Item No.:
1.3
15-Sep-2020
M0009-510-640

Foreword
Contents 2
1 General Information 3
31.1 Safety
2 Installation 4
42.1 Parts List 42.2 Getting Started 42.3 Installing Software
3 Operating Instructions 5
53.1 Operating Principle in brief 53.2 Connecting the SPCM 63.3 Graphic User Interface (GUI) 73.3.1 Operating Modes 83.3.2 Measurement Modes 83.3.3 Measurement Properties 93.3.4 Occurrences During Measurement 93.3.5 Measurement Result Display
4 Maintenance and Service 10
5 Appendix 11
115.1 Certifications and Compliances 125.2 Warranty 125.3 Exclusion of Liability and Copyright 135.4 Thorlabs Worldwide Contacts and WEEE Poilicy

We aim to develop and produce the best solution for your application
in the field of optical measurement technique. To help us to live up to
your expectations and constantly improve our products we need
your ideas and suggestions. Therefore, please let us know about
possible criticism or ideas. We and our international partners are
looking forward to hearing from you.
Thorlabs GmbH
WARNING
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully, before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
ATTENTION
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
NOTE
2 © 2020 Thorlabs

1 General Information
© 2020 Thorlabs 3
1 General Information
Thorlabs' Single Photon Counter Modules use a silicon avalanche photodiode to detect single
photons. The SPCM counters are sensitive to photons emitted in the 350 to 900 nm range with
the maximum sensitivity at 500 nm. They work by converting an incoming photon into a TTL
pulse in the detector, which is counted by the internal 31-bit counter. An additional SMA con-
nection offers a direct output pulse signal from the module that can be viewed on an oscillo-
scope or connected to an external counter.
An integrated Peltier element stabilizes the diode's temperature below the ambient temperature
to reduce the dark count rate. The two available models, SPCM20A and SPCM50A, have low
typical dark count rates of 25 and 150 counts per second, respectively, which allows them to
detect power levels down to 0.14 fW.
The active quenching circuit integrated into the diode of the SPCM enables high count rates. Its
high speed allows users to count a photon every 35 - 45 ns, depending on the model chosen.
The SPCM20A provides an active area of Ø20 µm and the SPCM50A offers Ø50 µm.
The SPCM includes a software package with GUI for out-of-the-box operation.
1.1 Safety
Attention
The safety of any system incorporating the equipment is the responsibility of the assem-
bler of the system.
All statements regarding safety of operation and technical data in this instruction manual
will only apply when the unit is operated correctly as it was designed for.
The SPCMxxA must not be operated in explosion endangered environments!
Do not remove covers!
Do not open the cabinet. There are no parts serviceable by the operator inside!
This precision device is only serviceable if properly packed into the complete original
packaging including the plastic foam sleeves. If necessary, ask for replacement pack-
aging.
Refer servicing to qualified personnel!
Only with written consent from Thorlabs may changes to single components be made or
components not supplied by Thorlabs be used.
All modules must only be operated with proper shielded connection cables.

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2 Installation
2.1 Parts List
Inspect the shipping container for damage.
If the shipping container seems to be damaged, keep it until you have inspected the contents
and you have inspected the SPCMxxA mechanically and electrically.
Verify that you have received the following items within the package:
1. SPCM20A (~/M) or SPCM50A (~/M)
2. Wall plug adapter (power supply 100-240 VAC / 6 VDC / 1.5 A)
3. USB 2.0 cable, A to mini B
4. Quick Start
5. CD with operating software
2.2 Getting Started
NOTE
Take care for proper air ventilation in order to ensure normal operation of the SPCMxxA.
Prior to connecting the SPCMxxA to a PC, please install software from the attached CD.
2.3 Installing Software
NOTE
The screenshots in this manual are related to a Windows®7 Operating System.
Insert the CD into your CD or DVD drive. If the installation screen does not appear automati-
cally, please execute
[CD Drive]:\Autorun\autorun.exe
After completing the installation you might be prompted to restart your PC.

3 Operating Instructions
© 2020 Thorlabs 5
3 Operating Instructions
3.1 Operating Principle in brief
The Thorlabs SPCMxxA uses a silicon avalanche photo diode (Si APD), operated in reverse di-
rection and biased slightly beyond the avalanche threshold (Geiger mode). An incident photon
generates charge carriers, which initiate a current pulse.
In order to enable the count of next incident photon, each current pulse must be “quenched” by
lowering the bias voltage below the avalanche threshold for a short time. After quenching the
bias increases again, this way enabling the APD for detection of the next photon. The Thorlabs
SPCMxxA use an APD with integrated quenching circuit, providing a high counting accuracy.
Photon initiated current pulses are counted. The counter is gated for a certain time (“bin”). Mea-
surement can be repeated in order to count the number of incident photons in subsequent bins.
For details, please refer to the full Operation Manual.
3.2 Connecting the SPCM
- Connect the wall plug adapter to mains outlet
- Connect the adapter’s DC output cable to the SPCMxxA
- Connect the SPCMxxA via the USB cable to your PC
- Switch on the single photon counter module. The green LED, located beside the DC power
input of the SPCMxxA, lights up.
Note
During a measurement, the green status LED is switched off in order to avoid stray light.
- Your operating system will recognize a new hardware and automatically start the driver in-
stallation.
- After completing, a message will inform you that the new hardware is installed and ready to
use.
Start the software by clicking the appropriate icon on the desktop; alternatively it can be
started from Windows button - Programs - Thorlabs - SPCM Series Software - “SPCM”.
As a next step, the Single Photon Counter Module needs to be connected to software. There-
fore, click to the icon in the toolbar or choose the appropriate function from the Device
menu
A device selection dialog opens

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The selected device is shown on a colored background. Click "Connect" - the selected hard-
ware is connected and the dialog window closes.
If no device is shown to be selected, click "Refresh Device List" button. Select the recognized
device and click "Connect".
Note
Multiple SPCM devices can be operated from a single PC by running a separate software in-
stance. The Device Dialog panel will show all recognized SPCM devices, an already connected
SPCM will be inactive (grayed out), so that only a free, available SPCM can be selected to con-
nect.
3.3 Graphic User Interface (GUI)

3 Operating Instructions
© 2020 Thorlabs 7
3.3.1 Operating Modes
The SPCM software offers five operating modes to be selected from a drop-down list:
-Manual Mode:The APD is biased beyond breakdown voltage internally. The counter is
started and stopped manually via the appropriate button in the software, at each "start"
command the counter is reset. No settings except Pulse Blind Time can be made. The
count result is updated 10 times per second and displayed numerically (Alignment display)
and graphically (tabs Graph and Bar).
-Free Running Timed Counter: The APD is biased beyond breakdown voltage at any time.
The counter is started / stopped by the internal timer. The timer is programmed via soft-
ware, this way defining the bin length and the waiting time between bins. The sum of bin
length and time between bins must not go below 0.020 ms. An additional Pulse Blind Time
can be set. After pushing the Start button, the timer begins to control the counter and inci-
dent photons are counted into bins until the Stop button is pressed. The results are dis-
played graphically and numerically, see Measurement Result Display .
-Externally Triggered Timed Counter: This operating mode is similar to the Free Running
Timed Counter mode, with the difference that the timer is started by an external trigger sig-
nal. The sensitive trigger edge (rising or falling) can be selected. The APD is biased bey-
ond breakdown voltage at any time. The counter is started / stopped by the internal timer.
The bin length is programmed via software. After pushing the Start button, the trigger is
armed and waits for the first pulse slope. When the selected trigger edge is detected, the
timer is started and photons are counted for a time, defined by the set bin length. After fin-
ishing the bin, the counter stops. With the next trigger slope, the count starts again. This
continues until the Stop button is pressed. The results are displayed graphically and numeri-
cally.
-Externally Triggered Counter: In this mode, the counter is not timed, but controlled (star-
ted and stopped) only by an external trigger signal. The sensitive trigger edge (rising or fall-
ing) can be selected. The APD is biased beyond breakdown voltage at any time. After push-
ing the Start button, the trigger is armed and waits for the first pulse slope. When the selec-
ted trigger edge is detected, the counter starts photon count until the next trigger pulse ar-
rives. As for this reason, the trigger period Tpdefines the bin lenght as well as the time
between subsequent bins. This counting process continues until the Stop button is pressed.
The results are displayed graphically and numerically.
-External Gating: The External Gating is similar to Externally Triggered Counter mode. The
significant difference is that the APD is not always biased beyond breakdown voltage, but
the APD bias is controlled by an external gating signal. The advantage of this active gating
is a lower probability to miss a photon: In previously described modes, the APD is biased
beyond breakdown voltage at any time. That means, it reacts on incident photons at any
time. This reaction includes also the activity of the quenching circuit; during the quenching
time (35 - 45ns) the APD is "blind" for incident photons. When the APD is gated actively, it
is armed with the arrival of the gating signal so that the first incoming photon can be coun-
ted. In External Gating mode, the counter is not triggered on a selectable edge, but enabled
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as long as a gating signal is present. The gating signal must be TTL level compatible, HI =
active.
3.3.2 Measurement Modes
In all operation modes, except for Manual Mode, the number of bins to be counted can be lim-
ited. This measurement mode is called Array Measurement. Array measurement allows high
measurement speed by limiting the number of bins; after completing the count is stopped
(Single Array) or restarted (Continuously) by the GUI. Check the appropriate box and enter
the number of bins to be counted.
In above example, the SPCM will count an array of 100 bins and the stop. If desired, the array
count can be restarted automatically by checking the box "Continuously".
Array size: A max. of 10,000 bins can be measured. For fast measurements (Bin Length +
Time between Bins < 0.020 ms), the max. array size is limited to 1,000.
3.3.3 Measurement Properties
Beside the measurement status (start time; for array measurement - duration and progress),
statistics of counted photons is displayed (number of bins, max. and min. photon count per bin,
average photon count and the span between the minimum and maximum count.
Note
The minimum photon count serves also as an indicator for counter errors:
- value = -1: During measurement, a counter overflow occurred (more than 2,147,483,647
photons counted)
- value = -2: During measurement, a bin was missed and could not be transferred to the GUI
- value = -3: Read error during loading data from a file
Finally, the current USB transfer rate is displayed.

3 Operating Instructions
© 2020 Thorlabs 9
3.3.4 Occurrences During Measurement
Displays the history of occurred during measurement error, which may lead to incorrect photon
count. In contrast to the display of the actual SPCM status in the status bar, in this child window
single error events are recorded until a new measurement is started.
3.3.5 Measurement Result Display
Graphical and auxiliary displays are arranged in 4 tabs:
-Alignment: This display is useful to adjust the optical setup. Beside the actual photon count
it brings up important information on the current measurement and device status.
-Table: This is a purely numeric display. The first two columns state bin number and the ap-
propriate photon count. In column remarks are stated deviations from normal operation for
the actual bin count (e.g., saturation level or over temperature).
-Graph: In this tab, the recent photon counts are displayed graphically. Areas of interest can
be zoomed, using the cursor (marked red) by click and drag to the desired region. Alternat-
ively, the zoom area can be selected numerically from the Zoom Dialog (click to the
icon).
-Bar: This display is similar to the Graph display, with the difference that each bin is displayed
as a bar.

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4 Maintenance and Service
Protect the SPCMxxA from adverse weather conditions. The SPCMxxA is not water resistant.
Attention
To avoid damage to the instrument, do not expose it to spray, liquids or solvents!
The unit does not need a regular maintenance by the user. It does not contain any modules
and/or components that could be repaired by the user himself. If a malfunction occurs, please
contact Thorlabs for return instructions.
Do not remove covers!
13

5 Appendix
© 2020 Thorlabs 11
5 Appendix
5.1 Certifications and Compliances
Category
Standards or description
EC Declaration of Conformity - EMC
Meets intent of Directive 2004/108/EC 1) for Electromagnetic Compat-
ibility. Compliance was demonstrated to the following specifications as
listed in the Official Journal of the European Communities:
EN 61326:2006
EMC requirements for Class A electrical equipment for measurement,
control and laboratory use, including Class A Radiated and Conducted
Emissions 2,3,4) and Immunity. 2,3,4)
IEC 61000-4-2
Electrostatic Discharge Immunity (Performance criterion B)
IEC 61000-4-3
Radiated RF Electromagnetic Field Immunity (Performance criterion
A)
IEC 61000-4-4
Electrical Fast Transient / Burst immunity (Performance criterion B)
FCC EMC Compliance
Emissions comply with the Class A Limits of FCC Code of Federal
Regulations 47, Part 15, Subpart B 2,3,4).
EC Declaration of Conformity - LVD
Compliance was demonstrated to the following specification as listed
in the Official Journal of the European Communities: Low Voltage Dir-
ective 2006/95/EC 5)
EN 61010-1:2001
Safety requirements for electrical equipment for measurement, control
and laboratory use.
UL 61010-1 2nd ed.
Safety requirements for electrical equipment for measurement, control
and laboratory use.
CAN/CSA C22.2 No. 61010-1 2nd
ed.
Safety requirements for electrical equipment for measurement, control
and laboratory use.
IEC 61010-1:2001
Safety requirements for electrical equipment for measurement, control
and laboratory use.
Equipment Type
Test and measuring
Safety Class
Class I equipment (as defined in IEC 60950-1:2001)
1) Replaces 89/336/EEC
2) Compliance demonstrated using high-quality shielded interface cables.
3) Emissions, which exceed the levels required by these standards, may occur when this equipment is connected to
a test object.
4) Minimum Immunity Test requirement.
5) Replaces 73/23/EEC, amended by 93/68/EEC.

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5.2 Warranty
Thorlabs warrants material and production of the SPCMxxA for a period of 24 months starting
with the date of shipment. During this warranty period Thorlabs will see to defaults by repair or
by exchange if these are entitled to warranty.
For warranty repairs or service the unit must be sent back to Thorlabs. The customer will carry
the shipping costs to Thorlabs, in case of warranty repairs Thorlabs will carry the shipping costs
back to the customer.
If no warranty repair is applicable the customer also has to carry the costs for back shipment.
In case of shipment from outside EU duties, taxes etc. which should arise have to be carried by
the customer.
Thorlabs warrants the hard- and/or software determined by Thorlabs for this unit to operate
fault-free provided that they are handled according to our requirements. However, Thorlabs
does not warrant a fault free and uninterrupted operation of the unit, of the software or firmware
for special applications nor this instruction manual to be error free. Thorlabs is not liable for
consequential damages.
Restriction of Warranty
The warranty mentioned before does not cover errors and defects being the result of improper
treatment, software or interface not supplied by us, modification, misuse or operation outside
the defined ambient stated by us or unauthorized maintenance.
Further claims will not be consented to and will not be acknowledged. Thorlabs does explicitly
not warrant the usability or the economical use for certain cases of application.
Thorlabs reserves the right to change this instruction manual or the technical data of the de-
scribed unit at any time.
5.3 Exclusion of Liability and Copyright
Thorlabs has taken every possible care in preparing this document. We however assume no li-
ability for the content, completeness or quality of the information contained therein. The content
of this document is regularly updated and adapted to reflect the current status of the hardware
and/or software. We furthermore do not guarantee that this product will function without errors,
even if the stated specifications are adhered to.
Under no circumstances can we guarantee that a particular objective can be achieved with the
purchase of this product.
Insofar as permitted under statutory regulations, we assume no liability for direct damage, indir-
ect damage or damages suffered by third parties resulting from the purchase of this product. In
no event shall any liability exceed the purchase price of the product.
Please note that the content of this document is neither part of any previous or existing agree-
ment, promise, representation or legal relationship, nor an alteration or amendment thereof. All
obligations of Thorlabs result from the respective contract of sale, which also includes the com-
plete and exclusively applicable warranty regulations. These contractual warranty regulations
are neither extended nor limited by the information contained in this document. Should you re-
quire further information on this product, or encounter specific problems that are not discussed
in sufficient detail in the document, please contact your local Thorlabs dealer or system in-
staller.
All rights reserved. This document may not be reproduced, transmitted or translated to another
language, either as a whole or in parts, without the prior written permission of Thorlabs.
Copyright © Thorlabs 2020. All rights reserved.

5 Appendix
© 2020 Thorlabs 13
5.4 Thorlabs Worldwide Contacts and WEEE Poilicy
For technical support or sales inquiries, please visit us at www.thorlabs.com/contact for our
most up-to-date contact information.
USA, Canada, and South America
Thorlabs, Inc.
[e-mail]
techsupp[email protected]m
UK and Ireland
Thorlabs Ltd.
[e-mail]
[e-mail]
Europe
Thorlabs GmbH
[e-mail]
Scandinavia
Thorlabs Sweden AB
[e-mail]
France
Thorlabs SAS
[e-mail]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
[e-mail]
Japan
Thorlabs Japan, Inc.
[e-mail]
China
Thorlabs China
[e-mail]
Thorlabs 'End of Life' Policy (WEEE)
Thorlabs verifies our compliance with the WEEE (Waste Electrical and Electronic Equip-
ment) directive of the European Community and the corresponding national laws. Ac-
cordingly, all end users in the EC may return “end of life” Annex I category electrical and
electronic equipment sold after August 13, 2005 to Thorlabs, without incurring disposal
charges. Eligible units are marked with the crossed out “wheelie bin” logo (see right),
were sold to and are currently owned by a company or institute within the EC, and are
not dissembled or contaminated. Contact Thorlabs for more information. Waste treat-
ment is your own responsibility. “End of life” units must be returned to Thorlabs or
handed to a company specializing in waste recovery. Do not dispose of the unit in a litter
bin or at a public waste disposal site.

www.thorlabs.com